在分析现有群组最近邻查询中位置隐私保护的基础上，提出LBS中一种面向位置隐私保护的群组最近邻查询方法。该方法采用分布式系统结构，克服了集中式匿名系统结构所存在通信瓶颈和攻击重点的缺陷。在此基础上根据用户群组的运动状态信息，提出使用位置随机扰动和门限秘密共享的 Paillier 密码系统来安全地计算用户群组的质心位置。于是将用户群组的最近邻查询转换为此质心的最近邻查询。与现有的相关工作相比，理论分析表明所提有关方案能够在有效抵御现有的距离交叉攻击和共谋攻击下，实现灵活的群组最近邻查询，同时耗费较低的网络资源。%On the basis of analyzing the existing location privacy protections in GNN queries, a GNN queries method for location privacy protection in LBS was proposed. In this method, a distributed system structure for GNN was adopted to overcome the disadvantages of centralized anonymous system structure such as making a communication bottleneck and being a vulnerable point of attack. According to the motion status of a user group, two methods on the basis of this struc-ture, named location random perturbation and threshold secret sharing version of Paillier cryptosystem, were used to se-curely compute the center location of the user group. Then these users’ GNN queries had been turned into NN queries of the group center. Compared with existing related work, theoretical analysis proves that the proposal can effectively resist against the existing distance interaction attack and collusion attack and achieve flexible GNN queries, while it costs lower network resources.
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